溶剂热法制备石墨烯/SnO2及其气敏性

采用溶剂热法制备了石墨烯/SnO_2(G/SnO_2)纳米材料,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)等对G/SnO_2进行了表征,研究了石墨烯的量和溶剂热温度对该纳米材料气敏性能的影响。实验结果表明,石墨烯可以调节SnO_2晶体的生长:当石墨烯上清液的量为1 mL、热处理温度为160℃时,制备的G/SnO_2纳米材料在室温下对氨气具有较好的气敏选择性和较高的灵敏度;且当气体体积浓度为1 000μL·L~(-1)时,对NH3的灵敏度为266.4,检出限达到了0.01μL·L~(-1)。     

理解电子波性的教学探讨

波性是原子或分子中电子的重要性质,但结构化学教材对电子波性概念的解释不够详尽。为降低学生在学习该概念时的难度,结合教学实践,尝试将电子波性的物理特征描述为微观环境中电子的运动没有确定的轨迹。通过详细的分析与讨论,多数学生较好地理解了电子波性的物理特征,并认识到正是电子的波性与粒性在不同条件下的转换,才产生了能同时体现出电子波粒二象性的衍射图谱。     

基于SOLO分类理论以教材为素材的命题实践研究——以“有机合成路线图题”为例

以有机合成路线图题的命制为例,展示如何挖掘并整合教材内容为命题素材,如何基于SOLO分类理论进行设问而命制成试题。     

新型2-取代氨基-5-(N-异丙基-9H-咔唑-2-基)-1,3,4-噻二唑类

以N-异丙基-9H-咔唑为起始原料,经取代、氧化、环合、酰化4步反应合成了7个新型2-取代氨基-5-(N-异丙基-9H-咔唑-2-基)-1,3,4-噻二唑类化合物（1a～1g）,其结构经¹H NMR, ¹³C NMR, MS(ESI)和元素分析表征。采用MTT法测定了1a～1g对5种肿瘤细胞的体外抗增殖活性。结果表明：1a～1g对人正常VEC细胞的抑制活性弱于5-FU。 1d和1e对人白血病细胞(K562)和人结肠癌细胞(HCT-8), 1e对人肺癌细胞(A549细胞),以及1g对人结肠癌细胞(HCT-8)的抑制活性（IC₅₀≤9.28 μmol·L^-1）均与5-FU相当。     

Approach to 2′-(Dialkylamino)-1-alkyl-4′H-spiro[indoline-3,5′-oxazole]-2,4′-diones and 1,3-Oxazin-4-ones via Cyclization of Vilsmeier Salts withα-Hydroxy andβ-Carbonyl Amides

A straiglitforward and efficient synthetic method of 2′-(dialkylammo)-l-alkyl-4′H-spiro[indoline-3,5′-oxazole]-2,4′-diones and 2-(dialkylamino)-5,6-dihydro-4H-naphtho[2,1-e][1,3]oxazin-4-one-derivatives have been developed from a-hydroxy andβ-carbonyl amides and various Vilsmeier salts.A wide range of heterocyclic compounds were obtained in excellent yields(up to 97%),which will provide promising candidates lor chemical biology and drug discovery.     

超急速爆发沸腾的傅立叶与小波分析

采用快速瞬态微型压力测量系统对脉冲激光加热下无水乙醇超急速爆发沸腾过程中液池内压力变化进行了测量,利用傅立叶变换、小波分析等理论工具对该过程的能量与频率特性进行了分析,并对汽泡群行为进行了理论推测.结果发现,爆发沸腾过程中压力信号频率处于MHz量级;在不同阶段气泡群行为具有不同特点.     

Research of the planar optical fiber Bragg grating hydrophone probe

This paper presents the planar Fiber Bragg Grating （FBG） hydrophone probe sensing principle, and theoretically and experimentally researches the probe structure sensitivity, the receiving sensitivity frequency response characteristic and the acceleration response property. Planar sheet is made of stainless steel, its thickness is 0.15 mm, its diameter is 15mm, and the length of hollow circular shell is 20 mm. For this size of the structure, the probe structure sensitivity is up to 23 fm/Pa, which is about 7300 times of the value of the bare fiber. The resonance frequency is 6.5 kHz, and the amplitude-frequency curve of the receiving sensitivity response is relatively flat within the frequency range of 100 Hz to 5.5 kHz. The output yielded by one unit acceleration （1m/s2） is equivalent to （2.52 to 3.26 Pa） acoustic pressure acting output. This probe structure is easy to form FBG hydrophone array by multiplexing technique. The research shows that this planar structure not only can form FBG hydrophone probe, but also can constitute optical FBG laser hydrophone probe. The structure can realize different bandwidth, different range acoustic pressure measurement by adjusting the geometrical size of the sheet.     

Generation of GHZ States via Deterministic Entanglement Concentration

We present the generation of six-particle Greenberger Horne-Zeilinger （GHZ） states via deterministic entanglement concentration and generalize the scheme to the case of 2N particles. We show that arbitrary 2N-particle GHZ states can be obtained with certain probability via entanglement concentration. This may provide a new perspective for the preparation of multi-particle GHZ states. This study is also an exploration on the theory of deterministic entanglement concentration.     

Comparison of Laser Performances of 5at.% Yb:Gd2xY2(1-x)SiO5 Crystals between Different Cutting Directions

We investigate the laser actions of 5at.% Yb:Gd_2xY_2(1-x)SiO₅ (Yb:GYSO; x=0.1) crystals with different cutting directions, parallel and vertical to the growth axis. Our results show that the cutting direction of the sample plays an astonished role in the laser operation. The sample cut vertically to the growth axis possesses the favourable lasing characteristics. Its output power reaches 3.13W at 1060nm with a slope efficiency of 44.68% when the absorbed pump power is 8.9,W. In contrast, the sample cut parallel reaches only 1.65W at 1044nm with a slope efficiency of 33.76% with absorbed pump power of 7.99W. The absorption and emission spectra of the two samples are examined and the merit factor M is calculated. Our analysis is in agreement well with the experimental results. The wavelength tuning range of the superior sample covers from 1013.68nm to 1084.82nm.     

Electronic Energy Levels in an Asymmetric Quantum-Dots-in-a-Well Structure for Infrared Photodetectors

Theoretical calculation of electronic energy levels of an asymmetric InAs/InGaAs/GaAs quantum-dots-in-a-well （DWELL） structure for infrared photodetectors is performed in the framework of effective-mass envelope-function theory. Our calculated results show that the electronic energy levels in quantum dots （QDs） increase when the asymmetry increases and the ground state energy increases faster than the excited state energies. Furthermore, the results also show that the electronic energy levels in Q Ds decrease as the size of QDs and the width of quantum well （QW） in the asymmetric DWELL structure increase. Additionally, the effects of asymmetry, the size of QDs and the width of QW on the response peak of asymmetry DWELL photodetectors are also discussed.